Embodiments of the present invention relate to amplification apparatus, and more particular to a transmitter having an amplification apparatus, and a method for regulation of the amplification apparatus.
In any electronic communication system a transmitter includes an output amplifier, i.e. an amplification apparatus, that boosts the power of a transmission signal to a level sufficient to allow for a reception of the transmission signal by a receiver. Particularly in a wireless communication system, such as defined by the GSM (Global System for Mobile Communication) standard or defined by UMTS (Universal Mobile Telecommunication Standard), the power level of a mobile unit has to be adjusted according to rules given by a base station.
In addition the output amplifier may be subject to strict constraints on linearity and efficiency. If the transmitter is using an amplitude modulation such as 8-PSK modulation used in GSM EDGE (Enhanced Data GSM Environment), the output amplifier has to be arranged so that the output signal is linear in relation to the input signal to avoid a distortion of the output signal.
The efficiency of the output amplifier is defined by the ratio of an outgoing power level at an output of the output amplifier to the power input into the output amplifier. The lower that ratio the more efficient the input power is brought onto the outgoing signal. This is advantageous if the transmitter is part of a mobile terminal having only limited power resources.